1. Field of Invention
The present invention relates to a draw press device that improves quality and strength of a panel when a panel is formed by a press process.
2. Description of Related Art
Generally, in a press processing, a plane material panel is disposed on a lower mold having pattern and an upper mold presses the panel on the lower mold to transform the panel.
For example, a vehicle maker develops 1000 or more body panels so as to make a vehicle, and a part of panel passes various press devices and goes through various processes such as a drawing process, a trimming process, a piercing process, a flanging process, a hemming process, and so on to be fabricated to a product panel. Here, the draw forming process plastically deforms material and more than 90% of the quality of the product panel is determined by the draw forming process.
Like this, a press device for a draw processing, as shown in FIG. 1, a lower mold 101 having a lower end surface shape of a product panel is mounted on a bolster 103 of a lower side, an upper mold 111 having an upper end surface shape of a product panel is mounted on a slider 109 of an upper side, and a panel is introduced between the lower mold 101 and the upper mold 111 to be pressed as a product panel.
In a draw press device as shown in FIG. 2, a lower mold 101 having a lower end surface shape of a product panel is mounted on a bolster 103 of a lower side, and a blank holder 107 is mounted on the bolster 103 disposed outside the lower mold 101 through a cushion pin 105.
And, an upper mold 111 having an upper end surface shape of a product panel on an upper side of the lower mold 101 is mounted on a slider 109 of an upper portion, and a material panel 113 that is introduced between the lower mold 101 and the upper mold 111 is pressed to be a product panel in a condition that a part of the material panel 113 is put on the blank holder 107.
However, a press device as describe above has a drawback that a curve is formed by a shortage of strength when forming a relatively wide panel product such as a door panel, a wood outer panel, a trunk rid outer panel, and a roof panel.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.